Lubricant pump



- uly 8 1969 s. A. HEZNDERSON 3,

N Fiie'd Aug. 9, 1967 Sheet LUBRICANT PUMP INVENTOR.

F1 4 STANFORD ews/5m Sheet 3 012 July 8, 1969 s. A. HENDERSON LUBRICANTPUMP Filed Au 9, 1967 ATTORNEY United States Patent 3,454,138 LUBRICANTPUMP Stanford A. Henderson, Snyder, N.Y., assignor to Gomco SurgicalManufacturing Corporation, Buffalo, N.Y., a

corporation of New York Filed Aug. 9, 1967, Ser. No. 659,458 Int. Cl.F01m 1/02; F16n 7/36; F03g 7/06 US. Cl. 18426 13 Claims ABSTRACT OF THEDISCLOSURE A pump for supplying lubricant to a device including areservoir for lubricant, a pumping chamber, a first check valve foreffecting communication between said reservoir and said pumping chamber,a second check valve for permitting flow of lubricant from said chamberto said device, means for periodically supplying heat to said chamber toeffect a pumping action, and expansion means for permitting lubricant insaid chamber to expand in response to increases in ambient tempreaturewithout causing said second check valve to open. In one embodiment thepump is incorporated as an integral part of a cover for the device to belubricated.

Background of the invention The present invention relates to an improvedpump for selectively providing charges of lubricant to a device.

In the past there have been lubrication pumps which wereheat-responsive, that is, they would pump lubricant in response to theheat generated by a device as, for example, shown in United StatesPatent No. 2,861,652. Devices of this type were relatively complex inthat they required heat-responsive members to provide the necessarymechanical movement for effecting the desired pumping action. However,devices of this type, because of their complexity, were subject tomalfunctions. There was no known way of effecting the necessary pumpingaction while eliminating the necessary mechanical movements. It is withan improved lubricant pump which overcomes the above describedshortcoming of prior devices that the present invention is concerned.

Summary of the invention It is accordingly the primary object of thepresent invention to provide an improved lubricant pump which pumpslubricant to a device without utilizing mechanical movements forproviding the pumping action.

Another object of the present invention is to provide an improvedlubricant pump which is capable of providing a single charge oflubricant to a device incidental to the starting of the device therebyobviating the possibility of unnecessarily feeding lubricant to saiddevice When it is not in operation, and which feeds said lubricantslowly as the device heats up thereby prolonging the lubricationprocess. A related object of the present invention is to provide animproved lubricant pump which provides charges of lubricant to a deviceat periodically timed intervals.

A further object of the present invention is to provide an improvedheat-responsive pump for delivering lubricant to a device in response tothe heat generated thereby but which will not deliver lubricant inresponse to small swings in ambient temperature.

A still further object of the present invention is to provide animproved self-contained lubricant pump consisting of a heat conductiveconduit having check valves therein which will take in a charge oflubricant when it cools and will discharge the lubricant due to itsexpansion when it heats. Other objects and attendant advantages of icethe present invention will readily be perceived hereafter.

Broadly, the improved lubricant pump of the present invention includes alubricant reservoir, a housing containing a pumping chamber, a firstcheck valve interposed between the reservoir and the pumping chamber topermit lubricant to flow into said pumping chamber when said chambercools and a second check valve for permitting flow of lubricant fromsaid chamber to a device to be lubricated when the lubricant in saidchamber expands in response to being heated, and means for heating saidlubricant within said chamber to cause the expulsion of said lubricantthrough said second check valve. In addition, expansion means areassociated with the pumping chamber to permit the lubricant to expanddue to increases in ambient temperature without being discharged throughsaid second check valve. The preferred embodiment of the presentinvention incorporates the foregoing structure in the end cap or coverof a device to be lubricated. In another form of the present inventionthe improved pump of the present invention is incorporated within aheat-conductive length of tubing. Another modification of the presentinvention utilizes an external heating source for heating lubricantwithin the chamber, either incidental to the energization of the deviceto be lubricated or by means of a circuit which effects periodic timedheating of the lubricant chamber to thereby provide periodic dischargesof lubricant. The present invention will be more fully understood whenthe following portions of the specification are read in conjunction withthe accompanying drawings wherein:

Brief description of the drawings FIGURE 1 is a schematic sideelevational view partially in cross section showing the improvedlubricant pump of the present invention mounted on a device containing arotating element such as a air pump or compressor; FIG- URE 2 is a sideelevation view of a preferred embodiment of the improved pump of thepresent invention wherein it is incorporated into the end cap or coverof a device; FIGURE 3 is a view partially in cross section takensubstantially along line 33 of FIGURE 2; FIG- URE 4 is a bottom planview taken substantially in the direction of the arrows 44 of FIGURE 2;FIGURE 5 is a side elevational, semi-exploded view, partially in crosssection showing the construction of the check valves used in the pump ofFIGURES 1-4; FIGURE 6 is a side elevational view showing the parts ofFIGURE 5 assembled; FIGURE 7 is a side elevational view, partially incross section showing another embodiment of the improved pump which isincorporated into a length of tubing such as a nipple; FIGURE 8 is afragmentary view partially in cross section, showing the lubricantpumping chamber with a resistance heating element incorporated thereinto supply the heat required for pumping; FIGURE 9 is a fragmentary sideelevational view of the pumping chamber, but showing a heating coilwound around the outside of the chamber; FIGURE 10 is a schematic wiringdiagram showing the manner of energizing the heating coils of FIGURES 8or 9 incidental to energizing the device which is to be lubricated so asto provide a single charge of lubricant; and FIGURE 11 is an electricalwiring diagram showing how the heating coils of FIGURES 8 or 9 can beenergized cyclically to periodically provide charges of lubricant to adevice.

Description of the preferred embodiments In FIGURE 1 one embodiment ofthe improved lubricant pump 10 is shown mounted on a device such as anair compressor or pump 11 having a shaft 12 mounting a rotor 13 which islocated within chamber 14, the shaft 12 being driven by a suitableelectric motor, not shown. The

pump 11 may be of the type in which spring biased vanes, not shown, moveradially of rotor 13 in following the surface of chamber 14 to therebytrap and move air which is supplied from a suitable inlet and moved to asuitable outlet conduit. While an air compressor or pump has beenmentioned above, it will be appreciated that the improved pump of thepresent invention can be used with any conceivable type of device havingmoving parts which require periodic lubrication.

The improved pump includes a housing 15 forming a pumping chamber 16.Mounted at one end of housing 15 is an elbow 17 which in turn mountsnipple 18 carry-ing an inlet check valve 19. An oil reservoir 20 havinga cap 21 mounted thereon contains a body of lubricant 22. Check valve 19will permit lubricant to flow from reservoir 20 into chamber 16 but willnot permit flow in a reverse direction. Therefore, once a charge oflubricant has been taken into pumping chamber 16 from reservoir 20, itcannot pass out of the chamber through inlet check valve 19. The otherend of housing 15 is mounted on cover 23 which carries outlet checkvalve 24 which permits flow of lubricant from chamber 16 onto the end ofportion 25 of shaft 12. Cap 23 and housing 15 are preferably fabricatedfrom heat-conducting metallic material so that the heat generated bydevice 11 will be transmitted to chamber 16 through cap 23 and housing15. Chamber 16 is full of lubricant and when this lubricant expands dueto the heat conducted thereto, it will cause outlet check valve 24 tounseat to permit flow of lubricant onto the end portion 25 of shaft 12.Since this shaft is rotating, the lubricant will travel radially alongthe wall of chamber 14 to provide lubrication.

It can be seen that there will be a gradual discharging or weeping oflubricant into chamber 14 from chamber 16 when outlet check valve 24opens. This discharging or weeping occurs as long as the temperature ofchamber 16 is increasing and will cease when the temperature stopsincreasing or falls. The weeping of lubricant from chamber 16 providesimproved lubrication because the lubricant is discharged gradually overa relatively long period of time as the device 11 heats up. After thedischarging has been completed, the valve will close and no moredischarging of lubricant will occur until chamber 16 has been refilled.This refilling occurs when housing 15 cools, that is, after the device11 stops operating, at which time a vacuum will be created in chamber 16which will cause outlet check valve 24 to remain closed and inlet checkvalve 19 to open to permit lubricant 22 from reservoir 20 to enterchamber 16. Upon subsequent start-up, the above described cycle ofproviding a charge of lubricant to chamber 14 via outlet check valve 24will be repeated.

The check valves 19 and '24, which are identical, are shown in greaterdetail in FIGURES 5 and 6. Each check valve includes a centralcylindrical collar or sleeve 26 which is press-fitted into the member inwhich it is positioned. This collar includes an end flange 27 whichforms a seat for one end of compression spring 28, the other end ofwhich bears on flange 29 formed integrally with cylindrical sleeve 30which is mounted on stem 31 of the valve member by means of a pin 32formed integrally with stem 31 which extends through aperture 31' insleeve 30 and is staked thereto. It is to be noted at the present time,as can be seen from FIGURES 1 and 5 and 6, that sleeve 26 is of greaterdiameter than sleeve 30 so that sleeve 30 may travel axially within thebore in which the check valve is located. There is a clearance betweenthe outside of sleeve 30 and the inner wall of the chamber to permitlubricant to travel past sleeve 30. Formed integrally with stem 31 is afrustoconical poppet valve 33 which terminates at base 34 which forms ashoulder. An annular groove 35 is formed on valve 33 and this groovereceives a resilient O-ring 36 which seats on frustoconical valve seat37 of housing 18 (FIG. 1) or frustoconical valve seat 38 of end cap 23.

Whenever there is a suflicient build-up of pressure in chamber 16,poppet valve 33 and O-ring 36 will be forced off of its seat. This willpermit lubricant to flow through the space between the housing and theouter surface of sleeve 30 and through the inside portion 37 of sleeve26 and through the oversized aperture 38 formed by flange 27 whichprovides a clearance between it and stem 31. This type of action occursthrough both valves 19 and 24 which are identical to the structure shownin FIGURES 5 and 6. It will be appreciated that whenever there is nopressure tending to unseat the poppet valve 33, spring 28, which is incompression, will force the O-ring 36 onto its seat by virtue ofproviding a force tending to separate sleeves 30 and 26.

At this point it is to be noted that the springs 28 are calibrated topermit the valves to open only when there is a temperature rise inexcess of a predetermined number of degrees. However, it is undesirablethat the valves open with swings in ambient temperature. If thisoccurred, there would be a pumping action and this could result inpumping substantial quantities of oil or lubricant into chamber 14 whenthe device was not being used. In order to obviate this possibility,O-ring 36 in each valve is sufliciently resilient so that it willcompress, especially in inlet valve 19, to provide the extra volumewithin chamber 16 which may be required to accommodate the expansion oflubricant which is experienced due to an ambient temperature rise. Thiscompression of O-ring 36 occurs before spring 28 can compress to permitoutlet valve 24 to unseat. It can thus be seen that the embodiment ofFIGURE 1 provides a pumping action in response to the heating oflubricant within chamber 16 without requiring mechanical devices toprovide the necessary motion to effect a pumping action.

In FIGURES 2, 3 and 4 the preferred embodiment of the present inventionis disclosed. In this embodiment, the improved lubricant pump of thepresent invention is entirely incorporated into end cap 39 of acompressor or air pump. Cap 39 includes a base 40 having a plurality ofspaced apertures 41 which receive suitable fastening members such asscrews for attaching the end cap 39 to the remainder of the compressorhousing. A housing 42 is cast integrally with cap 39 and includes alubricant reservoir 43 having a cap 44 mounted thereon. A pumpingchamber 45 is also mounted in housing 42 and is separated from reservoir43 by common wall 44. An inlet check valve such as 19 fits into bore 46with sleeve 26 being pressed into said bore and O-ring 36 seating onfrustoconical seat 47. A removable plug 48 is inserted into the end ofchamber 45. A second bore 49 is located in housing 42 and receivessleeve 26 of outlet check valve 24 in press-fitted relationship with theO-ring 36 of the check valve seating on frustoconical valve seat 50.Bore 49 is in communication with pumping chamber 45 through bore 51 inwall 44. As can be seen from FIGURES 2 and 3, plugs 52 and 53 are placedin wall 54 of housing 42 inasmuch as this wall must be bored in order todrill bores 51 and 46, respectively. The end cap 39 is fabricated frommaterial which is a relatively good conductor of heat so that the heatgenerated by the operation of the pump or compressor on which end cap 39is mounted will be conducted to the lubricant in chamber 45 to cause itto expand and thus unseat the outlet check valve from valve seat 50 toforce the lubricant into the device to be lubricated, as explained aboverelative to the embodiment in FIGURE 1. After the device is shut off andit cools, a vacuum will be created in pumping chamber 45 which willcause the inlet check valve to be unseated from its valve seat 47 andthus permit lubricant to pass into pumping chamber 45 from reservoir 43.As noted above, the check valves which are inserted in bores 46 and 49are identical to those shown in FIGURES 5 and 6 and it is thereforedeemed that a detailed repetition of the manner of operation of saidcheck valves is not necessary.

In FIGURE 7 a further embodiment of the present invention is shown. Thisembodiment discloses a lubricant pump 55 which may be installed as aunit for lubricating any type of device with single charges oflubricant. This pump 55 is essentially a length of heat-conductive pipe55' which is preferably fabricated from brass or copper having good heatconducting qualities. Conduit 55 is tapped at 56 to permit it to beattached to inlet and outlet conduits, with the inlet conduit being incommunication with a suitable lubricant reservoir, not shown.Alternatively, the inlet portion 57 may be made of a suitableconfiguration to contain a reservoir of lubricant and a cap may beinserted into threaded tapped portions 56 associated therewith. As canbe seen, pump 55 includes a pumping chamber 58 haing an inlet checkvalve 19 and an outlet check valve 24. The inlet and outlet check valves19 and 24 are identical in all respects to the check valve described indetail above relative to FIGURES 5 and 6 and it is therefore believedthat a detailed description is unnecessary. These check valves aremounted within pump 55 by having the center sleeves 26 press-fittedwithin annular members 59 which are in turn press-fitted into the bore60 of unit 55, Members 59 each have a cylindrical bore 61, whichreceives sleeve 26, and a frustoconical seat 62 for receiving the O-ring36. The mode of operation of the embodiment of FIG. 7 is the same as theembodiment of the preceding figures, nagmely when pipe 55' heats up,there will be a build-up of pressure within chamber 58 and outlet checkvalve 24 will be open to permit lubricant to flow in the direction ofthe arrow. When pipe 55 cools, a vacuum will be created within pumpingchamber 58 to cause inlet check valve 19 to open to permit lubricant toflow into chamber 58 from inlet portion 57 which may be considered asthe lubricant source or reservoir.

A further modification of the present invention is shown in FIGURE 8which may be added to any of the devices shown in the preceding FIGURES1 to 4 and 7. In certain cases there may not be a sufficient heat flowto the pumping chamber 63, which is analogous to pumping chamber 16 ofFIGURE 1, 45 of FIGURES 2 to 4, and 58 of FIGURE 7. Therefore, itbecomes necessary to heat the lubricant in chamber 63 for the purpose ofexpanding it and causing it to flow to the part to be lubricated. Tothis end, a resistance heater 64 is located within chamber 63, saidresistance heater being in communication with a source of electriccurrent through lead wires 65 which extend through the wall 66 ofchamber 63 by being held within nonconductive plugs 67.

In FIGURE 9 a still further modification of the present invention isshown wherein a heating wire 68 which is suitably coupled to a source ofelectric current through leads 69 encircles a pumping chamber wall 70for supplying heat thereto to expand the lubricant therein and providethe pumping action described in detail above. Housing 70 may beanalogous to housing 15 of FIGURE 1, housing 42 of FIGURES 2 to 4 orhousing 55' of FIG- URE 7.

In FIGURE an electric circuit is shown which can be used for energizingheating coil 71 which heats the lubricant, said coil 71 being analogousto heating elements 64 and 68 of FIGURES 8 and 9, respectively. As canbe seen from FIGURE 10, the device which is to be lubricated, such asthe compressor having a motor 72, is coupled across voltage source 73 byleads 74 and 75' and through switch 76, with heating coil 71 beingplaced across leads 74 and 75 in parallel with motor 72. Thus, whenevermotor 72 is energized by the closing of switch 76, heating coil 71 willbe energized simultaneously to heat the lubricant in the pumping chamberand cause it to expand to thereby be forced to the part to belubricated. It will be noted that once the switch 76 is closed, heatingcoil 71 will remain energized until switch 76 is again opened. This typeof system for heating the lubricant is suitable where the motor 72 willbe energized periodically for short periods of time.

In FIGURE 11 another circuit is shown for supplying heat to thelubricant in any of the pumping chambers described above. In thisrespect, the circuit includes a heating coil 77 which is analogous toheating coil 71 in FIGURE 10, said heating coil 77 being for the purposeof placement within a chamber, such as shown in FIG- URE 8 or inencircling relationship to a chamber as shown in FIGURE 9 and saidheating coil 77 can be used in conjunction with any of FIGURES 1 through4 and 7. The circuit of FIGURE 11 includes a voltage source 78 whichsupplies electric current to heating element 77 When switch 79 is closedvia lead 80, switch 79, lead 81, lead 82, contact 83, contact 84,bimetallic arm 85, lead 86, lead 87, lead 88, rheostat 90, lead 91,heating element 77, lead 92 and lead 93. It is to be noted that whenbimetallic element is cool, contact 84 is in engagement with contact 83to complete the foregoing circuit. In addition with the completion ofthe above mentioned circuit, there will be a flow of current throughheating coil 94 encircling bimetallic element 85. In this respect thereis also a circuit completed from source 78 through lead 80, switch 79,lead 81, lead 82, contact 83, contact 84, bimetallic element 85, lead86, lead 87, lead 95, rheostat 96, lead 97, heater winding 94, lead 98and lead 93 back to the voltage source. The heating circuit will bemaintained until bimetallic element 85 warps in the well-known manner tocause contact 84 to move out of engagement with contact 83 whereupon theentire circuit to lubricant heating element 77 is disrupted. Whenbimetallic element 85 cools and warps so that contact 84 engages contact83, the foregoing circuit will be reestablished. The making and breakingof the foregoing circuit will cause periodic energization of heatingcoil 77 to cause the pump associated therewith to periodically supplycharges of lubricant to the device to be lubricated. As noted above,there is a rheostat 96 in the circuit of bimetallic heating coil 94 andthe adjustment of the resistance of rheostat 96 will determine thelength of time that it takes for bimetallic element 85 to be heated soas to thereby in turn determine the cycle of operation of the heatingcircuit. Rheostat associated with lubricant heating element 77 can beused to adjust the time required for heating the lubricant in thechamber. It will be appreciated that as element 77 heats and cools apumping action will be effected.

An alternate pumping arrangement can be obtained with a modified circuitsimilar to that of FIGURE 11 by immersing bimetallic element 85 in thelubricant in the pumping chamber and eliminating the bimetal heatingcoil 94. In this modification, heating coil 77 will heat the oil in thepumping chamber when contacts 83 and 84 are engaged and they willdisengage after the heated lubricant has caused flexing of the bimetal.After the lubricant cools bimetallic element 85 will deflect to causecontacts 84 and 83 to again engage and complete a heating circuitthrough element 77. In this modification the placing of bimetallicelement 85 and its associated contacts in the lubricant chamber permitsthe elimination of heating coil 94 and its related circuit.

It can thus be seen that the improved lubrication system of the presentinvention is manifestly capable of achieving the above numerated objectsand while preferred embodiments of the present invention have beendisclosed, it will readily be appreciated that it is not limited theretobut may be otherwise embodied within the scope of the following claims.

I claim:

1. A pump for supplying lubricant to a device which is to be lubricatedcomprising a housing including a pumping chamber, a first check valvefor permitting flow of lubricant into said chamber, a second check valvefor permitting flow out of said chamber to said device, and meansoperatively associated with said housing for supplying heat to saidpumping chamber to thereby expand said lubricant in said chamber andthus cause said lubricant to be forced through said second check valveto said device, said first check valve opening on the cooling of saidchamber to permit flow of lubricant into said chamber. I

2. A pump as set forth in claim 1 including first and second springmeans for normally biasing said first and second check valves,respectively, to a closed position.

3. A pump as set forth in claim 1 including expansion means forpermitting lubricant in said chamber to expand with changes in ambienttemperature without causing said second check valve to open.

4. A pump as set forth in claim 2 wherein said first check valveincludes a poppet valve, a valve seat, and a resilient member interposedbetween said valve and said valve seat for compressing when saidlubricant in said chamber expands, said resilient member having greatereffective resilience than said second spring means, whereby saidresilient member compresses before said second spring means permits saidsecond check valve to open, to thereby permit expansion of lubricant insaid chamber due to ambient temperature changes without causinglubricant to be discharged through said second valve means.

5. A pump as set forth in claim 1 wherein said means for supplying heatto said chamber comprises conductor means providing a heat path betweensaid device and said chamber.

6. A pump as set forth in claim 1 wherein said means for supplying heatto said chamber comprises an electrical heating coil for heating saidlubricant in said chamber.

7. A pump as set forth in claim 6 wherein said heating coil is locatedexternally of said chamber.

8. A pump as set forth in claim 6 including means for periodically andcyclically energizing said heating means.

9. A pump as set forth in claim 6 including expansion means forpermitting lubricant in said chamber to expand with changes in ambienttemperature without causing said second check valve to open.

10. A pump as set forth in claim 6 including first and second springmeans for normally biasing said first and second check valves,respectively, to a closed position, and wherein said first check valveincludes a poppet valve,

a valve seat, and a resilient member interposed between said valve andsaid valve seat for compressing when said lubricant in said chamberexpands, said resilient member having greater effective resilience thansaid second spring means, whereby said resilient member compressesbefore said second spring means permits said second check valve to open,to thereby permit expansion of lubricant in said chamber due to ambienttemperature changes without causing lubricant to be discharged throughsaid second valve means.

11. A pump as set forth in claim 1 wherein said pump comprises a capadapted to be mounted on said device, a first chamber forming areservoir on said cap, and wherein said pumping chamber comprises asecond chamber on said cap, conduit means for effecting communicationbetween said first and second chambers, and wherein said first checkvalve is mounted in said conduit means.

12. A pump as set forth in claim 4 including expansion means forpermitting lubricant in said chamber to expand with changes in ambienttemperature without causing said second check valve to open.

13. A pump as set forth in claim 12 wherein said pump comprises a capadapted to be mounted on said device, and wherein a first chamberforming a reservoir on said cap, and wherein said pumping chambercomprises a second chamber on said cap, conduit means for effectingcommunication between said first and second chambers, and wherein saidfirst check valve is mounted in said conduit means.

References Cited UNITED STATES PATENTS 2,007,482 7/1935 Stitt l84262,861,652 11/1958 Small. 2,867,224 1/1959 Martiniak et al. 23 X2,954,845 10/1960 Mincra 6023 X 3,099,222 7/ 1963 Poliseo 6023 X HALL C.COE, Primary Examiner.

US. Cl. X.R. 6023

